48" brick oven from Melbourne

[cobblerdave]

Re: 48" brick oven from Melbourne

G'day
That shiracsate is going to introduce more water into the build better to put it on now and dry it at the same time as your brick work. Dry your brick then put wet shiracsate and then put your dry insulation both the brick and the dry insulation will absorb the water..... Back to square one.
With the entranceway there's no need to buttress in my opinion. Its tied back to the dome and in reality is not a big structure. It has become practice to buttress more and more nowdays as more ovens entrances are separated from the main structure by a heatbreak. I buttressed mine cause along the way it gained an arch entrance and a 630 mm wide brick chimney and is now 2 and a half bricks deep. ( makes a cool outdoor fire place)
Regards dave

[Dario]

Re: 48" brick oven from Melbourne

Thanks Steve, Dave and everyone.

I am still not convinced that your outer arch does not need to be buttressed.

I haven't change nothing about arch and i'm not going to buttressed i think i don't needed, hm time will tell. I like the way it looks and i could be wrong but i will take a risk.

Dave thank you for instructions for curing.

It a little late, but there is not release space on the arch form. I hope you can get the form out without damaging or cracking your brick work.

What material are you using for your chimney, if a SS vent pipe you may be okay not to buttress if it is going to be brick or stone you need to think hard about buttressing.

Russel you are right, it was hard to take the playwood out and i did chip few bricks but i manage to take it out with out further damage...
Stainless will go on the top as a chimney nothing fancy similar to this pictures.




When i put blanket on after curing my oven and i Cover with Shiracast layer i really never used one i don't know how hard is Shiracast. Can Shiracast help holding my front arch not to buttressed or it's just work as a insulator?
I know someone reply it works as a insulation i could be wrong?

Thanks Andrew and Colin...

Cheers Dario

[oasiscdm]

Re: 48" brick oven from Melbourne

Dario

Listen to Russell re getting arch firm out... You might have problems as it is one piece and will dislodge you arch. I would burn it out removing it as it burns.

and Dave re curing, I went with the dry temper approach over a month but with the blanket on to equalise the oven temperature do that it was even and now using for 4 months not one crack anywhere.

Dave and I discussed this approach for a bit and I liked it and it works I was driving moisture out for around 4 weeks. Put plastic over (Karachi suggestion) and you will see the moisture.

[Blunt Tool]

Re: 48" brick oven from Melbourne

Looking good Dario!

You have really set a pace. I will have to follow your build more closely or it will be finished by the time I check back in!

Have you decided yet if you will finish it as an igloo or a house style? Sorry if I missed that somewhere. I would be tempted to buttress your outer arch, as I don't think the upper bricks are tied to the dome and this is where most of the outward pressure will come from. If you are planning to finish as a house this is pretty easy to do and incorporate into the overall finish.

Andrew

[UtahBeehiver]

Re: 48" brick oven from Melbourne

Dario,

It a little late, but there is not release space on the arch form. I hope you can get the form out without damaging or cracking your brick work.

What material are you using for your chimney, if a SS vent pipe you may be okay not to buttress if it is going to be brick or stone you need to think hard about buttressing.

[cobblerdave]

Re: 48" brick oven from Melbourne

Hey Dario - Looking good. Starting the curing fires without the insulation should not cause a problem. Moving the moisture out will be easier without the blanket will be easier.

I am still not convinced that your outer arch does not need to be buttressed.

G'day Steve
Our posts seem to have crossed. I get your point on the buttressing. Dario has a short entrance tied back to the dome. It should not require any extra buttressing.
G'day Dario
My oven has grown some what over time so I buttressed mine as just a sensible precaution, you don't I believe need to follow my example.
Regards dave

[cobblerdave]

Re: 48" brick oven from Melbourne

G'day
I think of oven curing in two parts. Drying and heat tempering.
Your ovens come ahead in a very short space of time so its still full of water. Take the time to slowly tease that out. Water boils at 100C . I litre of water expands to roughly 1500 litre of steam. That's expansion that will crack an oven.
Low and slow .... No flame to heat the top unevenly from the base.
A 150 watt garden light to start things off . Start burning some charcoal beads ( no flame) in a metal tray,a old baking dish ? Keep it going for 5 days
Then insulate and start the 100c next day 200c flame in the oven process to heat temper your oven.
Don't forget that that you have a heated oven at this stage and you can also bake some food as you go..... Its not just a pizza oven
Regards dave

[Greenman]

Re: 48" brick oven from Melbourne

Hey Dario - Looking good. Starting the curing fires without the insulation should not cause a problem. Moving the moisture out will be easier without the blanket.

I am still not convinced that your outer arch does not need to be buttressed.

[Dario]

Re: 48" brick oven from Melbourne

G'day ,

Thanks everyone for the input to get where i am today with my WFO.
This is what i have done yesterday and today, slowly coming to a shape and looking good .
What you guys think could i slowly start curing my Oven Before i put Ceramic Blanket on and any recommendation would be much appreciate.
Here is few pictures.

Thank you Dario

[kanoer54]

Re: 48" brick oven from Melbourne

The reference to the AEI link to the arch and buttressing was a wealth of information. Wish I had seen this document when I was figuring out my dome and arches. thanks Greenman.
jon

[NCMan]

Re: 48" brick oven from Melbourne

building an oven is a bit of work and the extra effort to get it close as you can to right is worth the doing. Imho

+1..........

[david s]

Re: 48" brick oven from Melbourne

If the cracks are bad just render over them again. Don't start adding more insulation over the oven now. Your outer shell only serves to keep out the weather. Use an acrylic render over your cement render, but wait until you've had around 10 decent cooking firings, otherwise trapped moisture may create some blistering under the acrylic layer. You can paint over the acrylic render with any acrylic house paint, it works fine.

[Acrigg]

Re: 48" brick oven from Melbourne

Hi David,

Thanks for the advice, I did layer the perlite/vermiculite cement over the dome without a blanket 3-4 inches. I left it about a week before rendering.

If been starting the fires small and growing then to reduce and cracking. Only a few small cracks so far.

If it gets to bad then I'll put down some blanket or fiberglass insulation and apply another layer of perlite and render again.


What sould I seal the outer skin with to reduce water soaking in. It is open to the elements. I have read people use an acrilic sealer?

[david s]

Re: 48" brick oven from Melbourne

Hey Dario,

Sorry for the delay,


I insulated my dome with perlite cement with a bit of fire clay added to the mix. I then rendered over with home brew, cement lime fireclay sand 1:1:1:3

If I get to much heat loss I'll do another layer but as the other fellas said I think there will be plenty of thermal mass.


I'm curing my oven over the week and will do my first real fire and cooking this weekend .

This sounds to me like a recipe for outer shell cracking. 3:1:1:1 is too rich a mix and you are likely to get cracks. In addition, if you layered perlcrete directly over your dome without a blanket layer between it and the dome it's likely to turn to steam very rapidly unless you dried the perlcrete out really well before applying the render. Remember that around 1/3 of the perlcrete volume is water and the greater part of that needs to be removed. If you end up with some big cracks in the outer shell, leave them and continue to use the oven until it's dry, then give it another render layer and you should be ok.

[Greenman]

Re: 48" brick oven from Melbourne

Thermal mass and insulation are two different things. Not sure that the addition of fire clay will help with insulation and the thickness of the perlite cement or vermicrete is critical depending if any other insulation material is used.

Adequate insulation needs to be in place before the render goes over the top or it will just get untidy. Without decent insulation you could end up with a wham-bam-thanks mam oven. Building an oven is a bit of work and the extra effort to get it close as you can to right is worth the doing. IMHO